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US 6,281,360 B1Granted
Imidazopyridine derivatives and process for making them
AssigneeSynthon BV
InventorsGerrit Jan Bouke Ettema, Jacobus Maria Lemmens, Theodorus Hendricus Antonius Peters, Frantisek Picha
Life of this patent
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Abstract
Imidazopyridine compounds of the formula 1 are can be made in high purity, e.g. greater than 95% pure, by a process that use a novel intermediate of formula 5: wherein R1 and R2 each independently represent hydrogen or a lower alkyl group and Y and Z each independently represent a lower alkyl group. By this process, zolpidem, a commercial pharmaceutical of the formula 1 can be effectively made.
Claims30
A process, which comprises reacting a compound of formula (2):
- wherein Y and Z each independently represent a lower alkyl group;
- with glyoxylic acid or a compound of formula (6):
- wherein R3 and R4 each independently represent hydrogen or a lower alkyl;
- to form a compound of formula (5):
1 more element
A process which comprises:
- (a) reacting a compound of formula (2):
- wherein Y and Z each independently represent a lower alkyl group;
- with a compound of formula (6):
- wherein R3 and R4 each independently represent hydrogen or a lower alkyl;
- to form a compound of formula (5):
- (b))removing the alpha hydroxyl group of said compound of formula (5) with excess formic acid in the presence of palladium or rhodium supported on carbon to thereby form a compound of formula (3):
- and (c) converting said compound of formula (3) to a compound of formula (1) by reaction with an amidation agent:
- wherein R1 and R2 each independently represent hydrogen or a lower alkyl group.
5 more elements
A compound of formula (5):
- wherein Y and Z each independently represent a lower alkyl group.
Dependencies are inferred from the claim text.